Devices to variably set the control timing of gas shuttle valves are employed in modern internal combustion engines so that the phase relation between a crankshaft and one or more camshafts can be established variably within a defined angular range, between a maximum early position and a maximum late position. Such devices are also referred to as camshaft phasers. These camshaft phasers have a stator that is joined to a gear wheel, for instance, in an integral construction or by means of a non-positive connection, a bonded connection and/or a positive connection in case of two separate components, whereby the gear wheel is connected to a driving means such as a traction mechanism that is configured, for example, as a belt or a chain.
Such camshaft phasers often employ wing nuts to adjust the rotor relative to the stator, thus influencing the gas shuttle valves by means of camshafts arranged concentrically to each other, whereby the one camshaft configured as a hollow shaft is joined to the stator while the other camshaft arranged concentrically thereto is joined to the rotor.
The state of the art, for instance, German patent application DE 10 2008 051 755 A1, also discloses similar camshaft phasers which are provided with a drive element, a driven element and a spring element in order to variably set the control timing of gas shuttle valves of an internal combustion engine. In this context, the drive element can be operationally engaged to a crankshaft of the internal combustion engine, whereby the driven element can be operationally engaged to a camshaft of the internal combustion engine, and is arranged so that it can pivot with respect to the drive element, whereby the spring element is supported on the driven element on the one hand and on the drive element on the other hand, whereby, by means of the spring element, the driven element can be provided with a torque relative to the drive element, and whereby the spring element is in contact with at least one pin that is configured so as to be separate from the driven element and from the drive element. This pin can be configured like a screw, whereby it has a shank having an external thread and a pin at a distance from it, into which a socket for a tool has been created. A spring element is bent outwards in the radial direction and is in contact with such a pin that is attached to a side cover.
A similar camshaft phaser is also disclosed in Japanese specification JP 2003/120229, whereby a spring element is attached to a hex key. This spring is arranged so as to lie like a spiral in a plane.
U.S. Pat. Publ. No. 2007/0215085 discloses a similar camshaft phaser in which a spring is attached to the head of a bolt.
The fact that a spring can also be attached between the external thread of the shank and the screw head is also disclosed in U.S. Pat. Appln. No. 2007/0000462 A1.
These prior-art camshaft phasers are used in internal combustion engines such as gasoline or diesel engines and are in operational contact with chain or belt drives. The spiral springs known, for example, from Japanese specification JP 2003/120229, which are used in camshaft amplifiers having a barrel-type design employed to compensate for camshaft friction torques.